Electric circuit



Oct. 26, 1943. HYQDQ 2,333,010

ELECTRIC CIRCUIT Filed June 17, 1941 GAS EXHAll/STER PRE SSURE RESPDNS/ VE Inventor; M as aki H yQdo,

His Attorney Patented Oct. 26, 1943 ELECTRIC CIItCUIT Masaaki Hyodo, Yokohama, Japan, assignor to General Electric Com New York pany, a corporation of Application June 17, 1941, Serial No; 398,435 r :In Japan October 31, 1940 a 6 Claims. (01150-27) My invention relates to electric circuits,-and more particularly totelectric protective circuits for electric valve means t Electric valve means comprising a vessel within which spaced electrodes and a control member are mounted and towhich is connected an exhaust pump for maintaining the pressure within the, vessel at auvery low value have been widely used. It is found that pressure rises within the vessel interfere withzthe normal operation of the electric valve means and in the case of electric 1 valve: means having an immersion igniter type of controlmember render the control member inoperative to form a cathode spot and in this way control the timeof initiation of discharge between the anode and cathode of the electric valvemeans. vThisfailureof the control member to perform its normal' function is believed to. result from the wetting of the igniter of the control member with mercury and probably from the formation of an: amalgam on the surface of the control member due to the presence of oxidized mercury resulting vfrom a rise in pressure within the vesselhousing the electrodes of the electric valve means. If the control memberor igniter is energized after it fails to accomplish its normal function it rapidly deteriorates and in addition results in a Waste. of energy since the igniter is ineffective to render the electric valve means conductive. 'In accordance with the teachings of my invention I provide a new and improved protective circuit for electric valves which prevents energization of the control electrode thereof when the pressure within the vessel housing the electrodes of the electric valve rises to such a value as to ren der the control electrode ineffective to accomplishlits normal function.

.It is an object of my invention to providev a new and improvedelectric protective circuit.

It is another object of'my invention to provide anew and improved protective circuit for preventing the destruction of an immersion igniter type of control member by energization thereof when the pressure within: the vessel housing the igniter. and associated cathode rises above a pre- In the drawing the single figure is a schematic representational" one embodiment of my invention.

Referring now to thedrawing,'I liave shown my invention embodied in aprotectivesystem'for an electric valve means II] of the typecomprising a vessel or container ll within which are mounted an anode 12, a pool type cathode 13 of conducting liquid such as mercury, and an immersion i'gniter type of control member 14. The control member is formed of resistance material having a high specific resistance with respect to the specific resistance. of the liquid cathode and may be formed of a carbonaceou material such as silicon carbide. *The pressure within the vessel II is normally maintained at a very low value by means o'f-a suitable gas exhauster illustrated schematically by the numeral I5 and which communicates with the interior of the vesselby means of a conduit l6; While'the electric valve means H] has been illustrated as comprising the single anode 'l2 and pool type cathode l3,it will be apparent that various other arrangements of elec trodes may beemployed if desired.

In the particular embodiment illustrated the anode-cathode circuit is energized from an alternating current supply circuit ll by means of a transformer 18, the secondary winding Ill of which has one end terminal connected to the cathode l3 and the other end terminal connected with the anode l 2 through a direct current load circuit illustrated by the numeral 20.

electrode 14 normally functions to produce a cathode spot on the pool type cathode upon the passage of a predeterminedcurrent'therethrough; In the arrangement shown inthe drawing, the current through the control member [4 is controlled by an auxiliary or firing valve 2|, preferably of the type employing an ionizing medium,

such as. a gas or vapor, and comprising an anode 22, a cathode 23 and a control member or grid 24. The'cathode is connected to the control ondary winding 21 of a transformer having the primary winding 29 thereof connected to'a suitable source of alternating current voltage 30. If desired, the circuit 30 may be energized from the alternating current supply circuit I 1 through a suitabl phase shifting device (not shown). With the arrangement described thus far, it"will be readily understood that current periodically V As is well understood by those skilled in the art, the control for rendering said control circuit ineffective to energize said control member in response to a predetermined change in pressure within said vessel.

6. In combination, electric valve means comprising a vessel within which ar mounted an anode, a cathode, and a control member of the make-alive type, means tending to maintain a predetermined pressure within said vessel, a

control circuit for energizing said control member to control the conductivity of said electric valve means, and means responsive to pressure Within said vessel for rendering said control circuit ineffective to energize said control member under predetermined pressure conditions within said vessel.

MASAAKI HYODO. 

